Cabinet-type vending machines employing helical coils to selectively dispose numerous types of articles and packaged goods such as candies, nuts, chips and the like are old in the art. These mechanisms normally employ a plurality of vertically stacked, generally horizontally disposed and movable trays or shelves each of which usually has a plurality of front-to-rear generally rectangular troughs spaced laterally across the shelf and with a helical coil mounted in each trough. Such articles to be vended are positioned within convolutions of the coil such that, upon rotation of a particular coil in response to actuation of a control mechanism, one of the articles is projected into a delivery opening where it is available to a purchaser. In this type of arrangement, even though an end, e.g. of a package or wrapper may brush against the side of a wall or panel adjacent or preventing lateral movement of the product within the trough, such frictional drag to longitudinal feeding movement of the product does not lessen the efficiency of the structure.
Vending of tubular products, cans of soda, soup or the like present, however, a different problem. To place a row of cans within the convolutions of a helix for delivery similar to a package result in each can being canted or turned such that its longitudinal axis, its "rolling" axis is not normal or at right angles to the longitudinal axis of the trough. Thus tremendous friction forces are set up by each can vis-a-vis the floor and the sidewall of the trough, such that a conventional helix and drive motor are incapable of effectively handling such can or tubular product. The result has been the provision of serpentine racks for vending cans whereby pure gravity in most instances is used to deliver cans one-by-one to a delivery opening.